Requirements Documentation

Table of Contents

System Overview

The Elevator Simulation System is a comprehensive multi-elevator management system that simulates real-world elevator operations. The system manages two elevators operating across four floors (-1, 1, 2, 3) and handles various user interactions including floor calls, destination selections, and manual door operations.

Key System Components:

Use Case Diagram

graph LR
    subgraph "Elevator System"
        subgraph "User Interactions"
            UC1[Call Elevator from Floor]
            UC2[Select Destination Floor]
            UC3[Open Door Manually]
            UC4[Close Door Manually]
            UC5[Reset System]
        end
        subgraph "System Operations"
            UC6[Dispatch Elevator]
            UC7[Move Elevator]
            UC8[Auto Door Operations]
            UC9[State Synchronization]
        end
    end
  
    subgraph "Actors"
        USER[Building User]
        ADMIN[System Administrator]
        WEB_UI[Web Frontend]
    end
  
    USER --> UC1
    USER --> UC2
    USER --> UC3
    USER --> UC4
  
    ADMIN --> UC5
  
    WEB_UI --> UC9
  
    UC1 --> UC6
    UC2 --> UC6
    UC6 --> UC7
    UC7 --> UC8
    UC6 --> UC9
    UC7 --> UC9
    UC8 --> UC9

Use Case Descriptions:

Primary Use Cases:

System Operation Use Cases:

Class Diagram

classDiagram
    class ElevatorSystem {
        -List~Elevator~ elevators
        -Dispatcher dispatcher
        +requestElevator(floor: int, direction: string) 
        +selectDestination(elevatorId: int, floor: int)
        +updateState()
    }

    class Dispatcher {
        -List~Elevator~ elevators
        +addCall(floor: int, direction: string)
        +assignCallToElevator(floor: int, direction: string) Elevator
        +findBestElevator(floor: int, direction: string) Elevator
    }

    class Elevator {
        -int id
        -int currentFloor
        -string state // Replaced ElevatorState enum
        -string doorState // Replaced DoorState enum
        -string currentMoveDirection // Replaced MoveDirection enum
        -List~object~ assignedCalls // Replaced List~Call~ 
        +moveTo(floor: int)
        +openDoor()
        +closeDoor()
        +addCall(floor: int, direction: string) // Modified to reflect no Call class
        +update()
    }

    ElevatorSystem "1" *-- "1" Dispatcher : uses
    ElevatorSystem "1" o-- "*" Elevator : manages
    Dispatcher ..> Elevator : evaluates

Class Descriptions:

Core System Classes:

Data Model Classes:

Communication Classes:

Sequence Diagrams

1. External System Elevator Call Sequence

When an external system requests an elevator to floor A, the system first receives and parses the call command. The dispatcher evaluates all available elevators to calculate their estimated service times, then assigns the task to the elevator with the shortest wait time. Once assigned, the selected elevator begins moving upward, continuously updating its position until it reaches floor A. Upon arrival, the elevator automatically opens its doors and sends confirmation messages back to the external system. Throughout this process, the system maintains real-time synchronization with the web frontend to display current elevator status.

sequenceDiagram
    participant EXT as External System
    participant API as ElevatorAPI
    participant DISP as Dispatcher
    participant ELV as Elevator
    participant WS as WebSocketBridge
    participant UI as Web Frontend
  
    EXT->>+API: call_up@2
    API->>API: _parse_and_execute()
    API->>+DISP: add_call(2, "up")
    DISP->>DISP: create Call object
    DISP->>DISP: _process_pending_calls()
  
    loop For each elevator
        DISP->>+ELV: calculate_estimated_time(2, "up")
        ELV-->>-DISP: estimated_time
    end
  
    DISP->>DISP: select best elevator
    DISP->>+ELV: assign_task(2, call_id)
    ELV->>ELV: add Task to queue
    ELV-->>-DISP: task assigned
    DISP-->>-API: call processed
    API-->>-EXT: success/failure response
  
    ELV->>ELV: request_movement_if_needed()
    ELV->>ELV: state = MOVING_UP
  
    loop Until arrival
        ELV->>ELV: update() - movement logic
    end
  
    ELV->>ELV: arrive at floor 2
    ELV->>+API: send_floor_arrived_message()
    API-->>EXT: up_floor_2_arrived#1
    API-->>-ELV: message sent
  
    ELV->>ELV: open_door()
    ELV->>ELV: door_state = OPENING
    ELV->>+API: send_door_opened_message()
    API-->>EXT: door_opened#1
    API-->>-ELV: message sent
  
    ELV->>+WS: state update
    WS->>+UI: elevator state update
    UI->>UI: updateElevatorUI()
    UI-->>-WS: UI updated
    WS-->>-ELV: sync complete

Functional Requirements

FR1: Elevator Movement Management

FR2: Door Operation Management

FR3: Call Dispatching System

FR4: User Interface Requirements